Smoke-screen producer



J. H. HAMMOND, JR.

SMOKE SCREEN PRODUCER, APPLICATION FILED 05c. 30, 1916. RENEWED FEB. 20,1922.

1,429,238, I 1 Patent6dSept.19,l92Z.

I 4 SHEETSSHEET I. l I

HIS nrromsr' J. H. HAMMOND, JR.

SMOKE SCREEN PRODUCER. APPLICATION FILED DEC-30LI91 6- RENEWI-'.DFEB-20,1921 I L42938 I PatentedSeptlQ, 1922 4 SH EETS-SHEET 2.-

GASOLENE H/ ATTORNEY I I WITNESS RENEWED FEB-20,1922.

Patented Sept. 19, 1922..

4 SHEETS-SHEET 3. $2 ngvrguor Hm.

. HAMMOND, JR.

SMOKE SCREEN PRODUCER.

4 APPLICATION FILED DEC.30, 1916- 1,429,238.

' ms A 710mm J. H. HAMMOND, JR. SMOKE SCREEN PRODUCER. APPLICATION FILEDDEC.30. 191s. RENEWED FEB. 20. 1922.

Patented Sept. 19

1922... 4 SHEETS-SHEET 4.

HIE/5170mm Patented Sept. 19, 1922.

v UNITED STATES- v 1,429,233. PATENT OFFICE.

JOHN HAYS ammonia, JR, or GLOUCESTER, MASSACHUSETTS.

SMOKE-SCREEN raonocn'n.

Application filed December so, 1916, Serial No. 139,902. -Renewedrebruar zo, 192a Serial 1%. $38,055.

To all whom it may concern:

Be it known that I, JOHN HAYs HAM- Mom), J r., a citizen of the UnitedStates, and

a resident of Gloucester, county of. Essex,

State of Massachusetts, have invented cer.

tain new and useful Improvements in .Smoke- Screen Producers, of whichthe following 'is' a specification. I i Some of the objects of thisinvention are 10 to provide improved means for produc ng large volumesof dense smoke to serve as a screen for purposes of warfare; to prov dean "improved smoke screen producer which may be controlled inresponse toradiant energy; to provide animproved methodof producing a smoke screen;and to prov de other improvements as will appear hGI'BIl'lafter. 1 Inthe accompanying drawings Fig. 1 is a perspective. view showing smokescreen producers inoperation; Fig. 2 a diagrammatic lon itudinal centralsection on line 2.2 of Fig. 3 of a smoke screen producer constructed inaccordance with this invention; Fig, 3 is a transverse section on line33 of Fig. 2; Fig. 4 a fragmentary top plan view of a portion of theproducer; Fig. 5 a diagrammatic side elevation of a modified form of asmoke screen producer constructed in accordance with this invention;Fig.. 6 a transversesection on line 66 of Fig. 5; Fig. 7 a fragmentaryside elevation of a further modification of this invention; and Fig. 8 atransverse section on line 88 of Fig. 7.

Referring to the drawings, one embodiment of. this invention comprises asmoke screen producer which includes an elongated air tight fire-box ,10having a bottom wall 4i) 11 and two substantially parallel side walls 12extending upwardly from the bottom wall 11.- The upper portions of theside walls 12 are turned inwardly and converge upwardly and areconnected at their upper edges by a substantiallyhorizontal top wall 13which is oblong and substantially rec-- tangular in plan View. When thissmoke screen producer is in operation the lower portion of the fire-box10 is filled with pitch or other suitable smoke making substance 14,

which when suflic'iently heated under conditions preventingcompletecombustion will produce large volumes-of dense smoke. In Figs. 2and 3 this pitch 18 shown as having been liquified and as 'filling'thefire-box to a depth-indicated bythe horizontal line 15.

series of main torches pr For heating'the pitch or other smoke producing substance. .14 within the fire-box 10,

the upper inclined portions of the two side walls 12. areproyidedresfiefctively with two unsen burners 25.

These main torches 25 fitsnugly in: apertures provided therefor in-thecorrespondin side walls and are inclined inwardly an downwardly"in sucha manner that the long-i1 tudinal axes of the main torches coincide withlines which intersect a common line extending longitudinally through thefire-box 10 arranged in a vertical plane extending centrally andlongitudinally through the fire-box. These'main torches 25 arecon-.nected by branch pipes 26 to a'main supply pipe 27 which is controlledby a valve 28 y and which leads from a tank 29 containing gasoline orother suitable liquid fuel under pneumatic pressure, or anysuitable'gaseoiis fuel under pressure, for supplying the main torches25. The-flow of fuel'through each main torch 25 may be adjusted in awell known manner by means of a needle valve 30 with which each maintorch 25 is provided.

For vaporizing the gasoline in the main torches 25, and 'for ignitingthe gasoline vapor as it flows into the fire-box from the torches, eachof the main torches 25 is pro- 35 which is arranged beneath the maintorch 25 and which extends inwardly and up ,wardly through anopeningprovided theresupply pipe 36 leading from the source '29 of liquid fueland arev kept constantly burning in order to maintain the inn'enends ofvided with a relatively small auxili'ary'torch I the main torches 25 atsuitable temperatures and to ignite the gasoline vapor whenever it ispermitted to be generated in the main torches. The inner end of eachmain torch by the action of the flames of the auxiliarytorches 35, theauxiliary torches 35 being arranged to direct their flames upon thesebaflle plates37 respectively.

For facilitating the partialcombiistion of the pitch or other smoke"roducing substance 14 in the fire-box, a sha t {10 extendslongitudinally and horizontally through the fire- .100 I 25 ispreferably surrounded by a fiat annular only after the able bearings 41provided therefor in the opposite ends of the fire-box 10. and the shaft40 is arranged to be rotated by an electric motor 45 orother suitablemotor which, in

the form shown, acts through, gears 46, and

4T-to drive the shaft 40 through the intermediary of the friction clutch48. i The shaft 40 is provided with a gpluralityof. rigid prongs 49rigidly secured thereto, and radiating therefrom. I The shaft 40, withthe prongs49 carried thereby..begins to rotate pitch or other substance14 has been sufiiciently softened by the action of the heat from themain torches 25. The motor 45 is arranged to be controlled in responseto radiant energy, as hereinafter described. and after the motor hasbeen energized the friction clutch 48 permits the motor to rotatewithout rotating the shaft 40 and the prongs 49 carried thereby untilthe pitch 14 has been sufiiciently softened.

For discharging the smoke from the firebox 10 any suitable smoke stack55 is provided which communicates with the interior of the fire-boxthrough any suitable opening 56 provided therefor in one end of thefirebox.

- For regulating the amount of air which is permitted to enter thefire-box 10 the top wall 13 of the oven is provided with a {plurality ofopenings 60..which are arranged to be controlled by a horizontal plateor damper 61 whiclais slidably mounted upon the upper surface of the topwall 13 of the fire-box.

and which is slidably held between two cleats 52 secured to the top wallof the oven and overlapping the upper surface of the damper 61.

For controlling the operation of this improved smoke screen producer inresponse to radiant energy transmitted from a distant station, areceiving-system for radiant energy is provided. comprising an antennaor open aerial circuit- 74 which is carried by the boat or other movablebody upon which the smoke producer is mounted, and which isgrounded asat- 75 in any suitable manner. This antenna 74 has in series therewith acoil 76 which is inductively connected to a secondary coil 77 which isin a closed oscillatory circuit including a variable condenser 78 andwhich is arranged to control a gaseous detector 79 or any other suitabledetector. The detector 7 9 is arranged to control in a well known mannera circuit including a battery or other source of electrical energy 80and a relay 81 which controls a normally open circuit including abattery or other source of electrical energy 82 and a solenoid 83.

The valve 28, which controls the flow of The ends of this shaftmaaesecombustible fluid to the main torches 2b, includes and is controlled bya valve stem 84 upon which is loosely" mounted a pinion 85 which engagesa rack 87 which is carried by a'piston rod 88 which is arranged toreciprocate through one'end of a' cylinder 89, and which hassecuredtoits'inner end a piston 90 which is normally pressed inwardly ortowards the left, viwing'Fig. 3, by a spiral spring 91-a rranged withinthe cylinder 89 and surrounding the pistonrod SSfHetween the piston 90and the right hand endofthe cylinder 89. I v, a

The cylinder 89 is arranged to receive compressed air through a pipe 95which leads from a tank96 or other suitablesource of supply ofcompressed air. The air tank 96 is preferably arranged above thegasoline tank 29 and communicates with the gasoline tank through pipe 97opening into the upper portion of the gasoline tank '29. The inlet ofcompressed air-into the left hand end of the cylinder 89 from the pipe95, and the outlet of compressed air from the left end-of the cylinder89 through an exhaust pipe 97 provided therefor, are controlled by avalve which is arranged to be reciprocated by a spring pressed core 98which projects within the solenoid 83 and which is arranged to beactuated thereby.

Pivotally secured to the pinion 85 is a spring pressed pawl 100 which isarranged to actuate a ratchet 101 which is rigidly secured to the valvestem 84, and which in the form shown is provided with four teeth. Theconstruction of the valve 28 and its actuating mechanism is such thateach time an impulse of radiant energy is received by the antenna 74.the valve stem 84 will be rotated through a single step of ninetydegrees. and when the valve stem 84 is in a iven initial position or hasbeen rotated through two steps or 180 degrees therefrom communicationwill be established between the tank 29 and the main torches 25, andwhen the valve stem is in either of its two other positions n0 gasolinewill be permitted to flow from a the tank 29 to the main torches 25.

For controlling the operation of the electric motor 45,,a disc ofinsulating material is rigidly secured to one end of the valve stem 84.and is provided with two diametrically opposed contact plates 111, andtwo brushes 112 and 113 are mounted upon any.

pole of which is connected by a conductor 7 .117 to one pole of themotor 45. The other brush 112 is connected by a conductor 118 with theother pole of the motor 45. The arrangement is such that when the valve28 is in either of its operative positions, the

circuit will be closed through the brushes 112 and 113, correspondingcontact plate 111, battery 116 and motor 45, thus energizing the motor,and when the valve 28 is in. either of its inoperative positions, thebrushes 112 and 113 will rest upon the insulating disc 110, and thecircuit through the brushes 112 and 113, battery 116 and motor 45 willbe broken thus deenergizing the motor.. By

this arrangement, the motor will be energized only when the main burners25 are in operation.-

In the operation of the improved smoke screen producer shown in Figs. 2and 3, the auxiliary torches 35 are kept continually 2 5 and the motor45 'will not be energized.

Consequently, normally, the motor 45 and the main torches 25 are not inoperation and no appreciable amount of smoke'is produced within thefire-box 10. When, however, it

is desired to operate the smoke producer,

the antenna 74 is energized by sending 'a suitable signal from thecontrol station and this causes the operationof the detector 79 and theclosing of the circuit through the battery 82 and solenoid 83, whereuponthe valve of the cylinder 89 is operated to close the ex- ,haust.97 andto admit compressed air from the tank 96 through the pipe 95, thus forcing the piston rod 88 outwardly and rotat T40 ing the valve stem 84 intosuch a position as to permit the gasoline or other liquid fuel to flowfrom the tank 29 through the pipe 27 and valve 28 and through the branchpipes 26 into the main torches 25, and to close the circuit through thebrushes 112 and 113 and motor 45. The main torches 25 are thus caused tooperate and to direct their flames upon the pitch or other readilycombustible material 14 within the fire-box 10, thus melting the pitchand permitting the shaft 40, with its prongs 49, to rotate to facilitatea partial combustion of the pitch and to prevent the formation of agreasy scum upon the upper surface of the pitch.

The damper61 is adjusted so as to prevent a complete combustion of thepltch, and

thus to cause the production of a maximum volume of dense smoke.

When it is desired to cause the cessation of the operation of the smokescreen producer, a second signal or impulse of radiant energy is causedto act upon the'receiving antenna 74, and this acts through the detector79, as hereinbefore described, to ro- 65 tate the valve stem 84 throughninety degrees and into a neutral position in which the flow of gasolinefrom the tank 29'to the main burners 25 is stopped by the valve 28,

and the circuit through the battery 116 and motor 45 is broken by thecommutator 110,

thus rendering the device inoperative. I

The modified form of this invention shown in Figs15 and 6, comprises aclosed stationary fire-box 125, having at one end,

controlled by a damper 129 which is mounted to slide longitudinally ofthefire-box in a fixed path, the damper 129 being provided With suitableopenings 129' arranged to cooperate with the openings 128 --in the upperwall of the fire-box when the damper 129 is in a suitable position.tudinally of the fire-box 125 and outside Extending longithereof, is asubstantially horizontal rigid rod 130 which is arranged to rotate abouta fixed axis coincident with its longitudinal axis'in bearings 131 whichare fixedly secured to the wall of the fire-box 125. Rigidly secured tothe rod 130 are a plurality of gasoline burners 135 of any well known orsuitable construction, which are arranged to extend through circularopenings 136 provided therefor in the wall of the fire-box 125 and toproject inwardly within the fire box. The portion of each burner 135which projects throughthe wall of the fire-box is provided with aspherical enlargement 137 which is coaxial with the rod 130 and which isarranged to completely close at all times the corresponding circularopening 136 through the wall of the fire-box. Adjacent I inoperativeposition (shown in full lines in Fig. 6,) into an operative position(shown in broken lines in Fig. 6), a crank armis rigidly secured to oneend of the shaft 130, and is pivotally secured at its free end to one ofwhich is pivotally secured to a disc 147 which is rigidly secured to oneend of a shaft 148, which is mounted in stationary bearing 149 to rotateabout a fixed axis coincident with its longitudinal axis. Rigidlysecured upon the shaft 148 is a ratchet 150 having two diametricallyopposed teeth and which is arend of a connecting rod .146, the other endI ranged to ue actuated by a spring pressed gear 148. T he gear 152 isengaged by a. rack 155 pawl 151 which is pivotally secured to a 152which loosely surrounds the shaft which is rigidly secured to one end ofa piston rod 156,'the other end of which is provided with a piston 157which is arranged to reciprocate in a fixed cylinder 158, the piston 157being held in its innermost position in the cylinder 158 by means of aspiral spring 159 surrounding the piston rod 156, and arranged withinthe cylinder 158. The cylinder 158 is provided with a valve casing 165,in which reciproc-ates a valve 166 which controls the admission ofcompressed air into and the exhaust of compressed air from the inner endof the cylinder 158. The valve 166 is controlled by a solenoid 83 whichis operatively connected, as hereinbefore described, to an antenna 74 insuch a manner that the system may be controlled in. response to radiantenergy.

A stationary tank 170 of compressed air or other fluid under pressure isconnected by a pipe 171 to the valve casing 165 for supplying thecylinder 158 with fluid under pressure, the assage of air from the pipe171 to the cyllnder 158 being controlled by the valve 166.

For supplying the burners 135 with gasoline or other liquid fuel, astationary tank 17 5 is provided, the upper portion of which ispreferably connected by pipe 176 to the air tank 170, he gasoline tank175 being in communication with the air tank 170 at all times throughthe pipe .176. The gasoline tank 175 is connected by a main pipe 177 andflexible branch pipes 178 with the three burners 135 respectively, andthe gasoline from the tank 175 is forced into the burners under thepressure of the air from the tank 170.

For increasing the amount of smoke produced by'the burners 135,: aplurality of syraying devices 180 are arranged in the upper portion ofthe fire-box 125, and in vertical alinement with the receptacle 140 forholding the pitch. These spraying devices 180 are connected by branchpipes 181 to a main pipe 182 which leads from a tank 183. or othersource of sup ply of any well known or suitable liquid fireextinguishing means, such for instance, as carbon tetrachloride or anyother suitable fire extinguishing. sub-- stance. The main pipe 182 iscontrolled by a vertically reciprocatory valve 185 which is pivotallyconnected to'on'e end" of an eccentric rod 186, the other end of whichis provided with an eccentric yoke or strap 187 which surrounds aneccentric 188 which is rigidly secured upon the shaft 130, and is soarranged that yvhen the shaft 130, is in an inoperative position, asshown in Fig. 6, the valve 185 will be maaaae overthe surface of thepitch 141 or otherv smoke producing material.

In this modified forni,the fire-box 125 may be provided, as hereinbeforedescribed, with a horizontal shaft 40 extending longitudinallytherethrough, and having rigidly secured thereto a plurality of rigidprongs 49 arranged to agitate the pitch 141, the shaft 40 being driventhrough a friction clutch 48 by motor 45, as hereinbefore described. Inthis form of the invention, the motor 45 is arranged to be controlled bya commutator comprising an insulating disc 190 rigidly secured to theshaft 148, and provided with a conducting segment 191 which is arrangedto be engaged by two brushes 192 which are mounted upon a stationaryinsulating block motor 45, and the other brush 192 is eonnected by aconductor 195 with one terminal of a battery 196, or other source ofelectric energy, the other terminal of which is connected by a aconductor 197 with the other terminal of the motor 45. The conductingsegment 191 is so arranged that whenthe burners 135 are in aninoperative position, as shown in Figs. 5 and 6, the conducting segment191 will be out of contact with, the brushes 192, but when the burners135 are in their operative position, as shown (in dotted lines in Fi 6,the conducting segment 191 will be in contact with the brushes 192,through the battery 196 and the motor 45, and thus cause a, rotation ofthe pinion 46, and a consequent rotation of the shaft 40 when the'pitch141 has been sufliciently soft- K ened, as hereinbefore described.

In the operation of the modified form of this invention shown in Figs. 5and 6, the parts are normally in the positions shown in full lines inthe drawings, and gasoline is being constantly forced into the burners135 through the main pipe 177 and branch pipes 178, and the main burners135 are constantly burning and normally directing their flameshorizontally over the pitch 141, but when an impulse of radiant energyis received by the antenna 74, the valve 165 will be operated to admitair from the pipe 171 into the inner end of the cylinder 158, and willforce and will close the circuit,

into the operative position indicated in dotted lines in Fig. 6, todirect the flames upon the upper surface of the pitch 141. At'the sametime, the circuit will be closed by the commutator 190, and brushes 192,through the battery 196 and motor 45, thus causing the rotation of theshaft 40 and the prongs 49, as soon as the pitch 141 has beensufliciently softened. At the same time that the burners 135 are movedinto operative position, the valve 185 will be opened'by the action ofthe 'shaft'130 and eccentric 188, and ,will permit fire extinguishingfluid to flow through the pipe 182 and branch pipes 181, into thespraying devices 180 from which it will be sprayed over the surface ofthe pitch 141. The combined action of the burners 135 and the sprayingdevices 180, when the amount of air admitted to the firebox 125 issuitably regulated by the damper 129, will produce large volumes ofdense smoke which will be permitted to exhaust through the smoke stack127. When it is desired to stop the production of smoke, a second signalof radiant energy is transmitted to the antenna, thus causing a secondenergization of the solenoid 83 andthe consequent outward movementof-the rack 155, whereupon the gear 152 will be rotated through a half arevolution, and the connecting rod 146 will be thus returned to itsinitial position, as shown in Fig. 6, thus returning the burners 135 totheir inoperative position and simultaneously closing the valve timebreaking the circuit through the.

185 to stop the flow of fire extinguishing brushes 192, battery 196 andmotor 45, and thus stopping the rotation of the motor and the shaft 40and prongs 49 carried thereby, whereupon no appreciable amount of smokewill be produced in the fire-box 125.

In the modified form of this invention shown in Figs. 7 and 8, thesystem comprises a stationary fire-box 200 which is arranged to containa predetermined amount of .pitch 201 or other smoke producing material,and provided with a plurality ofgasoline burners 205 extending snuglythrough one of the vertical walls of the furnace, and held infixedpositions, the burners being inclined downwardly and inwardly, soas to project their flames'over the upper surface of the pitch 201. Theburners 205 are con nected by branch pipes 2% to a main pipe- 177through which they are connected as hereinbefore described to the tank175 containin gasoline under pressure from the air tank 1 0, as shown inFig. 5.

For rendering the burners 205 operative or inoperative asubstantiallyhorizontal shaft 210 extends longitudinally through theoven 200,

shaft 210.

shaft 210, is a crank arni 211,'which is pivotally connected at its freeend to a connecting rod 146 which corresponds to the con necting rod 146shown in Figs. 5 and 6, and is arranged to be operated as hereinbeforedescribed,- to oscillate the shaft 210 through about forty-five degreeswhenever an im-..

pulse of radiant energy is received by the antenna 74, as hereinbeforedescribed.

Extending longitudinally within the firebox 200, is a flat baffle plate215, which is rigidly connected to the shaft 210 by radial arms 216. Theupper surface of the plate- 215 is preferably covered by a comparativelythick layer 217 of asbestos or other heat insulating material, which issecured to the plate 215. The plate 215 is so arranged with respect tothe shaft 210, that. when the shaft 210 is in its inoperative position,as shown in full lines in Figs. 7 and 8, the plate 215 will be arrangedhorizontally inthe path 'of the flames from the burners 205, and willprotect the pitch 201 from the action of the burners, and when the shaft210 has been oscillated through ninety degrees as a result of the actionof impulse of radiant energy,

the plate 215 will be correspondingly ro- 4 tated into the positionshownin dotted lines in Fig. 8 where it will be out of the pathof theflamesfrom the Journers 205 and will upon the shaft 210, the arrangement being7 such that when the bafiie plate 215 is in its horizontal position, asshown in Fig. ,8, the

valve 185 will be closed and will prevent the flow of fluid from thetank183 to the spraying devices 180, and when the baflie plate 215 is-inits vertical position, as shown in dotted lines in Fig. 8, the valve'185will be,

open and will permit fluid to flow from the tank 183 to the sprayingdevices 180.

The fire-box 200 may also be provided, as hereinbefore described, with.a horizontal shaft40 upon which are rigidly secured a pluralityof'prongs 49, the shaft -40 being arranged to be rotated as hereinbeforedescribed, by a motor 45, Which-is controlled as hereinbefore describedand shown in Tn the operation of the modified form of this inventionshown in Figs. 7 and 8, the burners 205 are constantly operated, and

and is arranged to rotate about an axis, normally no fire extinguishingfluid is per- I coincident with the longitudinal axis of the mitted toflow from the tank 183 through the Rigidly secured to one end of thespraying devices 180. The baflie' plate 215 is normally in the positionshown in Fig. 8 to protect the pitch 201 from the'action ofthe burners205. \Vhen an impulse of radiant energy is received by the antenna 74,the connecting rod 146 is actuated, as

hereinbefore described, to rotate the shaft tenna 74, and this causes,as hereinbefore described, a rotation of the shaft 1 18 through half arevolution, which acts to rotate the shaft 210 through about ninetydegrees to swing the plate 215 from an operative position into aninoperative position, as shown in full lines in Fig. 8. At the sametime,

the rotation of the shaft 210 acts to close the valve 185 .to stop thefiow of fire extinguishing fluid from the tank 183, and the rotation ofthe shaft 148 causes a corresponding rotation of the commutator 190 andthe consequent breaking of the circuit through the battery 196 and motor45, and the smoke producer is thus rendered inoperative.

Although only a few of the forms in which this invention may be embodiedhave been shown herein, it is to be understood that the invention is notrestricted to any I particular construction, but might be embodied invarious forms without departing from the spirit of the invention or thescofie of the appended claims.

aving thus fully described this inverition, I claim and desire to tersPatent of the United tates:

1. A smoke screen producer comprising a fire-box, a burner arran ed toproduce an imperfect combustion o smoke producing material in saidfire-box, means for inject-. ing fire retarding material in saidfire-box,

and meansresponsive to radiant energy for controlling said burner andsaid ln ectmg means.

, 2. A smoke screen producer comprising a fire-box,

a burner arranged to produce an imperfect combustion of smoke producingmaterial in said fire-box, means for injecting fire extinguishingmaterial into said firebox, and means responsive to radiant, energy forcontrolling said burner and said injectmg means. j I

3'. A smoke screen producer comprising a fire-box, means for producingan imperfect combustion of smoke producing material in said fire-box,and means for injecting fire retarding material into said fire-box.

a. A smoke screen producer comprising a rotect by fire-box, means forproducing a combustion of smoke producing material in said firebox,means for in ecting a fire retarding material into said fire-box, andmeans for simultaneously controlling said combustion means and saidretarding material injecting means. V c

5. A smoke screen producer comprising means for holding smoke producingmaterial, a burneroperative to cause a combustion of said smokeproducing material,

means for injecting fige retarding material against said smoke producingmaterial, controlhng means operative to control said burner, and meansgoverned by said confor controlhng said in ectrolling means tion means.

6. A smoke screen producer, comprising means for containing smokeproducing material, a burner for causing a combustion'of said smokeproducing material, means for controlling said burner, and meanscontrolled by said controlling means for injecting fire retardingmaterial against said smoke producing material.

7. A smoke screen producer, comprlsmg meansfor containing smokeproducing material, aburner for causing a combustion of said smokeproducing material, means responslve to radiant energy for controllingsaid burner, and means controlled by said controllin means for injectingfire retarding material against said smoke producing v material.

\ 8. A smoke screen producer comprisinga i fire-box adapted to containsmoke produc ing material, meansfor admitting air into said fire-box,means for producing a partial combustion of said material in saidfire-box, and means for injecting fire retarding material into saidfire-box.

9.3. smoke screen producer, comprlsmg afire-box adapted to contain smokeproducing material, adjustable means for admitting air into saidfire-box, means for producing a partial combustion of said ,material insaid fire-box, and means for irriecting fire retarding material intosaid fire- 10. A smoke screen producer comprising a fire-box adapted tocontain smoke producing material, adjustable means for admitting airinto said fire-box, a burner operative to cause a partial combustion ofsaid smoke producing material, means for ini jecting fire retardingmaterial into said fire-box, and controlling means operative to rendersaid burner and said injecting means either simultaneously operative orsimultaneously inoperative.

11. A smoke screen producer, comprising a firebox adapted tocontainsmoke producin material, a burner arranged to act upon saidmaterial, means for agitating said material, controlling means operativeto control said burner, and means controlled by said controlling meansfor controlling said agitating means.

12. A smoke screen producer comprising a fire-box', means responsive toradiant energy for heating smoke producing material in said fire-box,and means for agitating said smoke producing means'in said fire box.

13. A smoke producer comprising a firebox, means for heating smokeproducing material in said fire-box, and means automatically operativeto agitate said material in said fire-box.

14. A smoke'producer comprising a firebox, means for heating smokeproducing material in said fire-box, means for agitating said materialin said fire-box, actuating means, and a friction clutch connecting saidactuating means to said agitating means.

15. A smoke producer comprising a fire-- box provided with an outlet,means for regulating the admission of air into said firebox, means forheating smoke producing material in said fire-box, and means'autmmatically operative to agitate said material in said fire-box.-

16. A smoke producer comprising a firebox, a main torch for heatingsmoke producing material in said fire-box, and means limiting a supplyof oxygen thereto and means for injecting fire retarding material intosaid chamber.

19. A smoke screen producer comprising a combustion, chamber, means forproducing an imperfect combustion of smoke pro-.

ducing material therein, including means for limiting a supply of oxygentheretoand means responsive to radiant energy for controlling saidcombustion means and said limitin means. I

20. X smoke screen producer comprising means for holding smoke producingmaterial, a burner operative to cause combustion of said material, meansfor conducting air in limited quantities thereto, means said smokeproducing material, controlling means 'operatlve to control sald burnerand means governed by .said controlling means for controlling saidinjecting means.

21. A smoke screen producer comprising means for, holding smokeproducing material, a burner operative to cause combustion of said smokeproducing material,

. means for supplying air in limited quantities thereto and meanscontrolled by'radiant energy for controlling combustion.

22. A smoke screen producer comprising a combustion chamber adapted tocombine smoke producing material, adjustable means for admitting'air inpredetermined quantities into said chamber, means for controllingcombustion of said material and means operated by radiant energy foractuating said means.

Signed at Gloucester, in the county of Essex and State of Mass, this28th day of December, A. D. 1916.

JOHN HAYS HAMMOND, JR.

Witnesses:

LESLIE BUsWELL, ALBERT W. TRENOR.

.60 for injecting fire retarding material against

